Frequency control circuits such as for use in modulation measurement
USRE32314E · kind E · reissue
Assignee
Inventors
Key dates
| Filing date | Nov 8, 1978 |
| Grant date | Dec 23, 1986 |
| Priority date | — |
| Expiry date | Nov 8, 1998 |
Classification
- Technology area (CPC —)General
Abstract
A circuit responsive to an input signal having an unspecified frequency for converting it to a predetermined and constant means frequency, and particularly suitable for incorporation in a modulation measuring instrument, comprises a sampling mixer controlled by a variable frequency oscillator for sampling the input signal to produce an intermediate signal. The mean frequency of the intermediate signal is then compared with a reference representing a predetermined frequency value whereby to produce an error signal, and means responsive to the error signal adjusts the frequency of the oscillator in such a direction as to tend to hold the mean value of the frequency of the intermediate signal at the predetermined frequency value while preserving therein variations in amplitude and/or frequency due to amplitude and/or frequency modulation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.